The exemplary embodiments relate to the printing and marking arts. They particularly relate to printing systems with a processing unit providing substantial degrees of freedom in performing print jobs, and to print job scheduling for such printing systems. The following disclosure relates to printing and marking systems of all types, and to print job scheduling for same.
Printing systems have generally been designed with a strong emphasis on ease of use, and a lesser emphasis on exploiting to the fullest the capabilities of the underlying printing hardware. Accordingly, the user is typically given a few pre-selected controls each having a limited number of pre-selected settings. For example, an image contrast control may have a “photo-optimized” setting, a “graphics-optimized” setting, and a “text-optimized” setting.
Additionally, printing systems have generally employed only one or a few sheet paths, and only one or a few print job destinations. For example, a typical printing system may have a single marking engine, which bottlenecks sheet processing down to a single print path. The print media conveyor may be configured to limit sheet processing to a single print path. In such an arrangement, the print jobs are queued and performed sequentially, in a first in-first out (FIFO) sequence.
Most printing hardware uses a different amount of energy depending on whether it is preparing to print a page, printing a page, or waiting for a job to print. When it is idle, (i.e. waiting for a job to print), it uses the lowest amount of power, requiring only a small amount to listen on the network port. Before printing, it may need to warm up, causing it to draw substantially more power than when it is idle, possibly more power than when it is actually printing. Because no pages are actually being printed during the warm up time, more energy is used if a series of small jobs are printed at intervals than if they are printed immediately after each other.
FIFO print job queue/processing does not fully leverage the capabilities of intelligent jobs scheduling and can increase machine (image marking engine) powering up/powering down cycles and thereby increase power consumption and machine maintenance.